If you’re considering or are in a scenario where you need to license Windows 10 (or previous versions of Windows) in a virtual machine, then this how-to will give you definitive guide on licensing the Windows desktop OS for virtualization. I will cover both the scenarios of accessing Windows locally in a VM and from your data center (server based VM). It might not be everyone’s favorite topic to discuss, but luckily I really enjoy the topic to share my knowledge.

8 Steps total

Step 1: What are the license options to access a VM of Windows 10?

Windows Software Assurance (SA) and Windows Virtual Desktop Access (VDA) are the licensing options required when accessing a Windows desktop OS in a VM, either locally or remotely. Windows SA and Windows VDA are device based licenses, and under select Volume Licensing agreements available in a Per User license option.

Both Windows SA & Windows VDA provide flexibility for how you use Windows and include access to unique products with license rights not available through OEM or FPP licenses.

Windows 10 can be purchased via Retail (FPP) to run in a VM locally on the device. Windows 10 FPP licenses can be used in type 2 hypervisor scenarios (i.e. client Hyper-V, Boot Camp, Parallels, etc.) on the device. Only the primary user may remotely access Windows running locally on the device, and FPP licensing does not provide the license rights to access Windows remotely from a server.

OEM Windows 10 licenses are sold preinstalled on PCs from OEM manufactures. There are OEM System Builder Windows 10 licenses on the market but these licenses are for supposed to be only for System Builders who build and sell PCs and subject to the terms of the Microsoft OEM System Builder License.

Step 2: How do I license Windows Software Assurance?

Windows Software Assurance is available to license both Per Device and Per User.

Windows Software Assurance Per Device can be licensed with the Windows 10 Enterprise Upgrade license. Note you can no longer purchase ‘SA only’ within 90 days of purchasing a Windows desktop OEM/FPP license. Windows SA is included with certain VL agreements such as EA, Open Value & EES.

The requirement to license Windows 10 Enterprise Upgrade w/Software Assurance is a qualifying Windows desktop OS installed on your device(s). The qualifying OS requirement is essentially the Professional version of Windows (or better). There is a full list of qualifying Windows operating systems in both the Product Terms and the Volume Licensing guide for Windows 10 (pg.6).

With Windows Software Assurance Per User licensing, you license the individual, not the device, and that individual receives virtualization use rights for any device. To license Windows SA Per User, the primary user’s primary device must be licensed for Windows 7/8/8.1/10 Pro, Enterprise, or Education. Meaning you can only license Windows SA per User for a user who is the primary user of a device AND that device is a work device (not personally owned).

If your device is already licensed for Windows SA or Windows VDA Per Device and you want to move to Windows SA per User, the Windows SA Per User Add-on can be licensed here – at a discounted cost over the full SA/VDA per User.

Step 3: How do I license Windows Virtual Desktop Access (VDA)?

For devices or users that do not qualify for Windows Software Assurance, you can license the device or user with a Windows VDA license (which includes Windows SA benefits). Essentially the Windows VDA license is for devices or users that do not qualify or do not have Windows SA; such as thin clients, 3rd party owned devices and any device without Windows SA.

Windows VDA is now available to license both Per Device and Per User. There are no device license requirements to license either Windows VDA Per User or Windows VDA Per Device.
*Note that Windows VDA Per User and VDA Per Device are not available under all VL agreements.

The rights to access/run Windows desktop OS in a VM depends on where the VM will be located (locally or remotely from a server) and whether you have Windows SA or Windows VDA. The above chart breaks down these rights.

With Windows SA & Windows VDA, you may access up to four VM instances of Windows Enterprise (or downgraded OS) across up to four different servers at any one time. Windows SA and Windows VDA you also get the rights to the one instance of Windows 10 Enterprise (or downgraded OS) as the physical OS locally on the Licensed Device. For Windows VDA (Per Device), this local use right applies only if the Licensed Device is also licensed for Windows 10/8.1 Pro or Enterprise, or Windows 7 Professional or Enterprise.

Step 5: Bonus – FREE Microsoft Desktop Optimization Pack (MDOP)

The Microsoft Desktop Optimization Pack (MDOP) or suite, is now included with Windows SA & Windows VDA. This includes both the Per User and Per Device options for Windows SA & Windows VDA. Again, MDOP use rights are now included with Windows SA & Windows VDA, you do not need to purchase MDOP separately.

There are multiple licensing options given the each customers’ scenario and # of users. My licensing recommendations are below:

Server side licensing requirements:
1. Windows Server 2012R2 License – comes in multiple licensing options, the two I recommend in this scenario are:
a. Windows Server 2012R2 Datacenter – enables you to run unlimited instances of Windows Server with each license; or
b. Windows Server 2012R2 Standard - enables you to run up to two virtual instances of Windows Server with each license

2. Windows Server 2012 CALs – come in both Per Device and Per User and are required for every user or device accessing a your servers.

3. Windows Server 2012 RDS CALs – come in both Per Device and Per User and are required for every user or device accessing the Remote Desktop Services (RDS) functionality of Windows Server.

Step 7: Scenario – We’re planning on using VMware Horizon to allow our users to access Windows 7 Pro from a VM. Do we require Windows Server RDS CALs here, what licensing is required from Microsoft?

Given that you are using VMware’s solution, you will need to work with VMware to license their products.

If you are using Windows Server 2012, see the scenario above for licensing Windows Server. If you are NOT using Windows Server 2012R2 or any Windows Server RDS technologies, then you will not need any Windows Server licenses or CAL licenses.

Step 8: FAQs

Q. Why can’t we purchase an OEM Windows license and use it instead of Windows SA or Windows VDA?
A. Windows 10 through the OEM channel must be purchased with Windows preinstalled on the device. Technically Windows 10 OEM use rights do permit you to run Windows locally on the licensed device in a virtual OS. However, they do not provide use rights for accessing Windows running remotely from a server in a virtual OS. OEM licenses don’t permit remote access the VM running in a data center, no load balancing or reassignment rights, etc.

Q. How to I license a 3rd party contractor or temp worker that needs access to the VDI environment?
A. License the contractor with a Windows VDA device license in this scenario. When the contract/temp worker is done with the contract, you can “reassign” the Windows VDA license to a new device. This can only be done every 90 days though (minimum reassignment time).

Q. Is Windows SA or Windows VDA required even if I don’t use Microsoft’s Hyper-V?
A. Yes. Windows SA or Windows VDA are required regardless of 3rd party virtualization technology used. Any time a Windows desktop OS VM instance is accessed/delivered from a server to a device, that device or user needs a Windows SA or Windows VDA license to be licensed to access.

Q. Can I have a mix of Windows SA per User and Windows SA per Device under my VL agreement?
A. Yes. There are no enterprise wide commitments to going all Per User.

Q. We don’t qualify for the Per User options in Windows VDA, what are our options if our users have multiple devices they need to access Windows desktop OS VMs from?
A. You can license Windows VDA Per Device under Open Value licensing agreement. Windows VDA provides roaming use rights to Windows desktop OS VMs. This allows the primary user of the Windows VDA licensed device the rights to access the Windows desktop OS VMs from any 3rd party owned device (offsite). If the 3rd party device comes onsite, then it too would require a Windows VDA license.

Q. I need to access Windows XP Pro VMs remotely from my server, how can I license this?
A. Windows SA or Windows VDA would be the license option here from the Windows desktop OS perspective. However, you would already need to have access to the Windows XP Pro OS as the Microsoft Volume License Service Center (VLSC) only provides (n-2) Windows rights to Windows 7. You are licensed to run Windows XP Pro or previous versions, Microsoft just no longer provides the media/keys.

Q. Can I have a mix of Windows SA per User and Windows SA per Device under my VL agreement?
A. Yes. There are no enterprise wide commitments to going all Per User.

This guide is not meant to replace the Microsoft Product Terms or Volume Licensing Briefs, it’s more of a supplemental how-to. Always refer to Microsoft official documentation on licensing. The resources section provides the official Microsoft terms and licensing guides.

Microsoft partners can help guide you through the process of purchasing the licensing. Reach out to me if you have any questions.

@Eric, no you can only use a retail license (FPP) of Windows in a scenario where the VM will be run locally on your device (not server). When you access a VM of Windows 7 Pro or Windows 10 Pro remotely from a server, you don't license the server or the # of VMs, you license the access devices (or now users) accessing the Windows VMs.

@Eric, you need a Windows SA or Windows VDA per user or per device - for each device that accesses the VMs. You get the media and keys of Windows 7, Windows 8, Windows 10 Pro/Enterprise via the Microsoft VLSC website to create and activate your VMs.

Hi Chris,
Quick question.
I'm looking to buy a laptop with Windows 10 Pro OEM on it. I want to use this as a Hyper-V host to run 2 different Windows 10 Pro VM's locally. What do I need to do to license this properly? Buy 2 more Windows 10 licenses to cover the VM's or can these be created using the Laptop's OEM license without additional licensing?
Basically I manage the IT for two companies with 2 different domains which are not in a trust relationship and I want to have a domain joined VM for each network. I just wanted to know the best way to license this scenario.

Hi Paul,
Windows 10 doesn't inherently give you virtualization rights like a Windows Server license does. That said, you will need to either purchase 2 retail licenses of Windows 10 Pro to run locally on that device in a VM OR license your device with a Windows 10 Enterprise Upgrade w/Software Assurance license. Windows SA permits you to run up to 4 VMs locally on that device or 4 VMs remotely from a server.

@michaelasgian - Windows 10 Pro Retail allows for one VM running locally on a device. There are no access rights if you a retail license of Windows on a server. If you are running the VMs on a server with your devices accessing the server - you need a Windows SA or Windows VDA license for the accessing devices.

Work for small biz (~4 users) that wants to test Windows 10 in VM environment before deploying. Currently have mixture of Windows 7 with SA & Win 8.1 ENT with SA and employing the virtualization rights granted as part of this configuration to give users access to VMs hosted on Server. I am hearing mixed messages elsewhere on the web, so was hoping you can clarify... do we need to purchase a new license to test Windows 10 as a VM or are we granted access since all OS instances already covered by active SA ? If we are granted access do you know what version of Windows 10 to download on VLSC to create the Win 10 test VM with?

@matthewvita - Microsoft does have a Windows deployment toolkit for Windows 10 Enterprise, which includes all the tools for testing deployment: https://technet.microsoft.com/en-us/windows/mt604890.
That said, given that you're licensed for SA with the client devices, you can create your VMs using VL media and run/access them locally or from a server. You can create your VMs using Windows 10 Enterprise LTSB, CBB, or CB.. as well as Windows 10 Pro CBB, or CBB. LMK if you have any additional questions.

Thanks for the info! Quick follow up, if we follow the steps on the Windows Deployment toolkit link you shared would we wind up with operating VMs or just test versions? My boss, who is the resident tech guru and actually does the implementations, had a pretty frustrating situation a few years back when he was implementing our new serves whereby he did a similar test version to start with then discovered that he had to redo a ton of work because the test versions did not actually convert to real versions.... any thoughts on this concept of Test Vs. Real in terms of testing and implementing some Windows 10 VMs?

@matthewwvita - The media from the Windows deployment toolkit is limited and will expire. You would have to recreate your VMs for production, unfortunately there is not an upgrade path or ability to change the product key with the deployment toolkit.

What about the following scenario for VMs in an education environment using a cloud-based VM service (Skytap in this case).

Education use case where VMs are created, used for few months, then deleted for that user/class...what Windows 10 version and licensing model would you suggest so that they may be reused again and again when VMs are deleted/recreated?

Example would be 4 classes with 10 VMs each running for 3 months each, but only 20 maximum running concurrently.

Here is scenario. Customer has a laptop with OEM Win10 sitting on a shelf that they want to do a physical to VHD conversion and host in Hyperv. The unit runs what I believe is a fax program. It will not be used for remote access just management, but multiple users may access a share to grab the faxes or files.

So the way I take it they would need to purchase Win10 FPP and that is it. No VDA licenses required, correct?